TW201344161A - Self-calibrating tuning fork type sensor and its self-calibrating method - Google Patents

Abstract

This invention relates to a self-calibrating tuning fork type sensor and its self-calibrating method. The tuning fork type sensor comprises a diapason module, a controller, a sensing module, an output module, and a power module. The power module drives the tuning fork module to generate resonance frequency, and the amplitude of the resonance frequency is compared with a built-in voltage reference of a controller, after which a corresponding correction signal is outputted to the power unit so as to adjust the output voltage from the power unit to the diapason module and the controller. The controller is used to continuously compare the output voltage of the sensing module unit and the voltage reference built in the controller, and the output voltage of the power unit is continuously outputted and corrected to change the voltage outputted to the diapason module, until the voltage value of the sensing module unit is matched to the reference voltage, thereby achieving the purpose of self-calibration, allowing application by users to materials of different specific gravity and avoiding detection errors of the specific gravity due to environmental drift.

Description

Self-correcting tuning fork sensing device and self-correcting method thereof

The invention relates to a tuning fork type sensing device, in particular to a self-correcting tuning fork type sensing device and a self-correcting method thereof.

Various types of industries such as chemical barrel tanks, food industry, petrochemical industry, etc. use the tuning fork type sensing device to detect the height of the storage and liquid level, and then monitor the height change of the materials in the warehouse to further know its The stock of materials changes for the user's reference.

When the tuning fork type sensing device is used, a piezoelectric element is driven by a control module, so that a tuning fork can generate a resonant frequency, and the tuning fork can contact the material through the tuning fork to obtain a frequency signal and transmit the signal to the control module. And by calculating the change in its frequency, the depth of the material can be obtained, and the reserves of the material in the warehouse can be known.

However, different materials have different specific gravity, so the frequency signals generated when the tuning fork is in contact with the material are not the same, and thus the frequency change of the tuning fork to the control module is also different, thereby causing the tuning fork sensing device to calculate There is an error in the depth of the material. For example, the US Patent Publication No. US2006/0053863A1 discloses how to use a diagnostic method to determine the portion of the oscillation that is suitable as a drive. This design method does not diagnose the oscillation portion. The effects of the specific gravity of different materials are taken into consideration, which may cause calculation errors when the materials in the tank are changed.

Generally, the specific gravity of the same material will change with the change of temperature. For example, gasoline, alcohol or salt water may cause the specific gravity of the material to drift due to the temperature, so it is easy to cause the detection of the tuning fork type sensing device. In order to measure the error, in view of the above problems, it is necessary to review and seek a feasible solution.

In view of the above disadvantages of the prior art, the main object of the present invention is to provide a self-correcting tuning fork type sensing device, which mainly adjusts the sensing error of the sensing device by continuously signal feedback, thereby providing applicable to various types. Tuning fork sensing device for materials and various environments.

The technical means for achieving the above object is that the tuning fork type sensing device comprises: a tuning fork module comprising a tuning fork set and one or more piezoelectric elements, the tuning fork set being connected with the piezoelectric element; a controller It has an arithmetic function, which includes a plurality of analog-to-digital converters and one or more analog-to-digital converters. The controller has built-in voltage reference values for one or more tuning fork oscillations; one sensing module has more than one a differential amplifier, one or more filters, and one or more amplifiers, the differential amplifier outputs are respectively connected to an analog-to-digital converter of the filter and the controller, and the filter obtains an output signal from the differential amplifier and Output to the amplifier, the output of the amplifier is connected to the controller; an output module includes more than one protection unit and more than one status outputter, the output end of the protection unit is connected to the controller, the status outputter After the controller and the protection unit obtain the signal, the corresponding state control signal is output; a power supply unit is included therein. There are a plurality of DC-to-DC converters, and the output ends thereof are respectively connected to the foregoing controller, the sensing module, the output module and the tuning fork module, wherein the output of the DC-DC converter is connected to the tuning fork module. The piezoelectric element of the group and the analog-digital converter of the controller; the tuning fork type sensing device constructed according to the above structure mainly relies on the piezoelectric element of the tuning fork module to obtain power from the power supply unit, and the piezoelectric element The electrical energy and mechanical energy exchange characteristics are deformed, and the tuning fork group is resonated to generate a resonant frequency and amplitude, wherein the amplitude is output to the controller through the differential amplifier of the sensing module, and the built-in voltage reference value In comparison, if the matching is the same, if the preset voltage is insufficient, the controller will output a correction signal to the power supply unit to improve the output of the power unit to the piezoelectric element and the analog digital converter in the controller. The voltage further increases the amplitude of the piezoelectric element of the tuning fork group, and at the same time compares this voltage with the voltage reference value of the controller, and then subtracts the difference according to the difference The corresponding correction signal is repeated until the voltage reference value is met, and the self-correction is completed, so that the tuning fork group can be contacted with the material to be tested to obtain the correct material volume information; otherwise, the voltage reference value is too large. The controller can also output a correction signal to the power supply unit to reduce the voltage of the piezoelectric element, thereby reducing the amplitude of the tuning fork group, as described above, until the amplitude matches the built-in reference voltage value of the controller, and then The tuning fork group senses the volume information of the correct material for the user to properly monitor the volume of the material, so that the correction signal is repeatedly outputted by the controller to achieve the purpose of self-correction, and materials of different specific gravity and various materials. When the environment is in a state of drifting in specific gravity, the stock of materials in the warehouse can be correctly sensed to avoid user monitoring errors.

The main purpose of the present invention is to provide a method for self-correction of a tuning fork type sensing device. To achieve the foregoing objective, the controller in the sensing device performs the following steps, which include:

Start

b. The initial procedure reads the voltage reference value of the built-in material;

c. obtaining a voltage value of a resonant frequency;

d. comparing the magnitude of the voltage value, comparing the voltage value of step c with the voltage reference value, if not, performing step e, if yes, performing step h;

e. outputting a correction signal to increase or decrease an output voltage;

f. obtaining a corrected voltage value;

g. comparing the magnitude of the voltage value, comparing the corrected voltage value of the f step with the voltage reference value, and if not, performing the e step;

h. Output the calculated material signal;

The method for self-correcting the tuning fork type sensing device is mainly to initially output the amplitude of the tuning fork group by the differential amplifier of the sensing unit to the analog digital converter of the controller to obtain the original voltage value of a digital signal. The voltage is compared with the voltage reference value in the controller. If the two are different, the controller outputs a correction signal to the power supply unit, so that the DC-to-DC converter of the power supply unit can improve or reduce the signal according to the correction signal. The voltage output to the piezoelectric element is used by the tuning fork module to correct the amplitude of the resonant frequency, and the voltage value is fed back to the controller's analog digital converter, and further compared with the controller's voltage reference value to output another correction. Signal, repeating the e step to the g step, until the corrected voltage value matches the voltage reference value, and then outputting the corrected voltage value to the piezoelectric element for the tuning fork group to resonate to an appropriate amplitude, thereby using the material Contact to obtain the material signal, so that the self-correction can correctly detect the stock of the material to solve the amplitude Resulting in a variety of materials and sensing under different environmental problems caused by the detection error due to different specific gravity or insufficient.

Referring to FIG. 1 , the sensing device includes a tuning fork module 10 , a controller 20 , a sensing module 30 , an output module 40 , and a power unit 50 . The tuning fork module 10 is provided with a tuning fork set 11 (shown in FIG. 2 ) and a piezoelectric element 12 . The piezoelectric component 12 is mainly driven by the power supply unit 50 and the output of the sensing module 30 is returned. The tuning fork group 11 is further caused to resonate.

The controller 20 has an arithmetic function and is provided with a plurality of analog-to-digital converters 21, 26 and one or more digital analog converters 22. The controller 20 has a plurality of voltage reference values corresponding to different materials.

The sensing module 30 is provided with one or more differential amplifiers 31, one or more filters 32 and one or more amplifiers 33 connected in sequence, wherein the output of the differential amplifier 31 is connected to the filter 32 and the controller. An analog to digital converter 26 of 20.

The output module 40 is provided with one or more protection units and a status output unit 43. In this embodiment, two protection units are provided, which are an overcurrent protection unit 41 and a voltage protection unit 42, respectively. The unit 42 can detect the high voltage and the low voltage. The overcurrent protection unit 41 and the voltage protection unit 42 respectively obtain the output power from the power unit 50, thereby determining the output current and the output voltage of the power unit 50, thereby protecting the tuning fork. The sensor device avoids damage, and the state outputter 43 obtains a signal from the controller 20 and the overcurrent protection unit 41 and the voltage protection unit 42 to output a corresponding status signal, so that the user can know the tuning fork sense. Test equipment for abnormalities, information about materials or to control the feed switch to maintain material inventory.

The power supply unit 50 is provided with a plurality of DC-to-DC converters 51, and the output ends thereof are respectively connected to the aforementioned tuning fork module 10, the controller 20, the sensing module 30 and the output module 40, in this embodiment. The DC-to-DC converter 51 corresponds to the tuning fork module 10 so that the piezoelectric element 12 can be driven and the tuning fork group 11 can resonate.

The tuning fork type sensing device is further provided with a user 5 interface 60, which includes a testing unit 61 and a display unit 62. The testing unit 61 is connected to the controller 20, and is mainly used for simple testing by the user. Whether the tuning fork type sensing device has an abnormality, enabling rapid initial detection, and the display unit 62 receives the status signals of the controller 20 and the status outputter 43 of the output module 40, and displays the corresponding signals according to the status signals thereof. The light number or image, etc., for the user to immediately know the monitoring.

After the piezoelectric element 12 of the tuning fork module 10 is sent to the driving voltage for the first time, the piezoelectric element 12 is self-oscillated to generate a first clock signal, and the first clock signal is transmitted through the sensing module 30. A second clock signal is generated at the output of the amplifier 33, and the second clock signal is used to feedback the piezoelectric element 12, and the phase difference between the first and second clock signals can reach 90 degrees or 180 degrees. The second clock signal at the output of the amplifier 33 of the sensing module 30 is fed back to the tuning fork module 10 to provide a square wave signal of the piezoelectric element 12, and the square wave signal can provide the piezoelectric element 12 Maintain a fixed frequency oscillation.

In addition, in the embodiment, the controller 20 further includes a detection error unit 23, a current limiter 24, and a frequency calculator 25. The detection error unit 23 mainly detects the external force of the tuning fork type sensing device. Or the circuit relationship is such that the frequency calculated by the controller 20 frequency calculator 25 is within an unintended range, and the detection result is outputted to the display unit 62 of the user interface 60 for display or output through the output unit 40, and the limit is limited. The streamer 24 mainly reads the output signal of the overcurrent protection unit 41 in the output module 40. When an overcurrent condition occurs, the current limiter 24 turns off the state outputter 43, thereby reducing The current flow is prevented from causing damage due to continuous overcurrent generation, and the display unit displayed on the user interface 60 provides an alarm to ensure the safety of the use end. The frequency calculator 25 has a built-in preset value, which mainly calculates the frequency calculated by the sensing module 30, and further knows according to the frequency, what material is detected by the tuning fork group 11 . And displayed on the display unit 62 of the user interface 60 or outputted through the output module 40. When the frequency calculated by the frequency calculator 25 is less than or greater than the preset value, it is displayed on the display unit of the user interface 60. Therefore, the current tuning fork group 11 can be informed that its tuning fork may cause abnormal operation due to external impact damage or corrosion, and the state output device 43 in the output module 40 is turned off to ensure the safety of the use end.

The tuning fork type sensing device constructed as described above mainly drives the piezoelectric element 12 of the tuning fork module 10 through the power supply unit 50 to enable self-vibration, thereby causing the tuning fork group 11 to resonate, and then contacting the material by the tuning fork group 11 The material signal is obtained, and the material signal is outputted to the controller 20 through the sensing unit 30, so as to obtain the correct material inventory through the operation of the controller 20, wherein, in order to avoid the sensing error of the tuning fork group 11, the main transmission is The controller 20 obtains the output voltage of the differential amplifier 31 and the output voltage of the piezoelectric element 12 output from the power supply unit 50 to the tuning fork module 10, and initially outputs the piezoelectric element 12 to the piezoelectric element 12 for self-vibration through the power supply unit 50, and The tuning fork group 11 is resonated. At this time, the output amplitude voltage of the resonance of the tuning fork module 10 is obtained through the differential amplifier 31, and if it is equal to the reference voltage value of the controller 20, it is not necessary to change any setting, and by The controller 20 outputs the display unit 62 and the output module 40 to the user interface 60. If not, the controller 20 outputs a correction signal to the control power unit 50 to further adjust the power unit. 50 is output to the voltage value of the piezoelectric element 12, and the voltage value is fed back to the controller 20 to be compared with the voltage reference value again, and the operation is repeated until the output voltage of the power supply unit 50 and the voltage reference of the controller 20 are When the values are equal, the output voltage of the power unit 50 is output to the piezoelectric element 12, so that the tuning fork group 11 can be further oscillated to an appropriate amplitude to obtain a correct material signal, so that the user can correctly know. The stock of materials, and through the self-correcting function of the tuning fork type sensing device, allows the user to conveniently use materials of various specific gravity, and does not have to worry about the temperature shift caused by the temperature difference, and the detection error occurs. .

It can be seen from the above description that the present invention further provides the foregoing controller with a method for self-correcting the tuning fork type sensing device, which includes (as shown in FIG. 3):

Start

b. The initial procedure reads the voltage reference value of the built-in material;

c. obtaining a voltage value of a resonant frequency;

d. comparing the magnitude of the voltage value, comparing the voltage value of step c with the voltage reference value, if not, performing step e, if yes, performing step h;

e. outputting a correction signal to increase or decrease an output voltage;

f. obtaining a corrected voltage value;

g. comparing the magnitude of the voltage value, comparing the corrected voltage value of the f step with the voltage reference value, and if not, performing the e step;

h. Output the calculated material signal.

The method for self-correcting the tuning fork type sensing device is mainly to initially output the amplitude of the resonance frequency of the tuning fork group 11 to the analog digital converter 26 of the controller 20 by using the differential amplifier 31 of the sensing unit 30, thereby obtaining a digital position. a signal for the controller 20 to know the original voltage value of the amplitude through the digital signal, so as to compare the voltage with the voltage reference value in the controller 20, if the two are different, the controller 20 outputs a correction. The signal is sent to the power supply unit 50, so that the DC-to-DC converter 51 of the power supply unit 50 can correct or decrease the output voltage of the output voltage to the piezoelectric element 12 according to the correction signal, and then repeat the steps e to g until the corrected voltage value After the voltage reference value is matched, the corrected voltage value is output to the piezoelectric element 12, so that the self-correcting tuning fork sensing device can be realized, so that the tuning fork module 10 can resonate to an appropriate amplitude. And the sensor can correctly detect the stock of materials, and can be applied to materials of various specific gravity, and can also be used in the state of specific gravity caused by different environments, and The corrected voltage value is also fed back to the controller 20 and read by the analog digital converter 21, and compared with the voltage reference value, and then the controller 20 outputs another correction signal to the power supply unit 50, thereby outputting another corresponding The voltage value is corrected to increase the efficiency of its correction to stabilize the corrected value.

10. . . Tuning fork module

11. . . Tuning fork set

12. . . Piezoelectric element

20. . . Controller

twenty one. . . Analog digital converter

twenty two. . . Digital analog converter

twenty three. . . Detection unit

twenty four. . . Current limiter

25. . . Frequency calculator

26. . . Analog digital converter

30. . . Sensing module

31. . . Differential amplifier

32. . . filter

33. . . Amplifier

40. . . Output module

41. . . Overcurrent protection unit

42. . . Voltage protection unit

43. . . Status exporter

50. . . Power unit

51. . . DC to DC converter

60. . . user interface

61. . . Test unit

62. . . Display unit

Figure 1: is a block diagram of the present invention.

Figure 2 is a cross-sectional view of the present invention.

Figure 3 is a flow chart of the controller of the present invention.

10. . . Tuning fork module

11. . . Tuning fork set

12. . . Piezoelectric element

20. . . Controller

twenty one. . . Analog digital converter

twenty two. . . Digital analog converter

twenty three. . . Detection unit

twenty four. . . Current limiter

25. . . Frequency calculator

26. . . Analog digital converter

30. . . Sensing module

31. . . Differential amplifier

32. . . filter

33. . . Amplifier

40. . . Output module

41. . . Overcurrent protection unit

42. . . Voltage protection unit

43. . . Status exporter

50. . . Power unit

51. . . DC to DC converter

60. . . user interface

61. . . Test unit

62. . . Display unit

Claims (7)

A self-correcting tuning fork type sensing module, comprising: a tuning fork module comprising a tuning fork set and one or more piezoelectric elements, the tuning fork set being respectively connected with the piezoelectric element; a controller having an operation Function, which contains many analog-to-digital converters and more than one analog-to-digital converter. The controller has built-in voltage reference values for different materials. One sensing module has more than one differential amplifier. More than one filter and one or more amplifiers, the differential amplifier output is respectively connected to an analog-to-digital converter of the filter and the controller, and the filter obtains an output signal from the differential amplifier and outputs the signal to the amplifier. The output end of the amplifier is connected to the controller; an output module includes more than one protection unit and a status outputter, and the output end of the protection unit is connected to the controller, and the status output device is self-controller and protection After the unit obtains the signal, it outputs a corresponding status signal; a power supply unit having a plurality of DC-to-DC converters therein, and The output ends are respectively connected to the foregoing controller, the sensing module, the output module and the tuning fork module, wherein the output of the DC-to-DC converter is connected to the analog component of the tuning element module and the controller Digital converter. The self-correcting tuning fork sensing module of claim 1, wherein the tuning fork sensing module further comprises a user interface, comprising a test unit and a display unit; the display unit is separately controlled And the output module obtains its output signal; the test unit is connected to the controller. The self-correcting tuning fork sensing module of claim 2, wherein the protector of the output module comprises an overcurrent protection unit and a voltage protection unit; the overcurrent protection unit is configured to input current from the power supply unit. And output to the controller and the state output device; the voltage protection unit is capable of detecting overvoltage and overvoltage, which is input voltage from the power supply unit and output to the state output device. The self-correcting tuning fork sensing module according to any one of claims 1 to 3, wherein the controller further comprises a detecting error unit, a frequency calculator, and a current limiter; the detecting error unit Outputting to the display unit of the user interface or the status output of the output module; the frequency calculator obtains the output signal of the sensing module to calculate the signal frequency, and outputs the signal to the detection error unit; the current limiter is The output signal of the overcurrent protection unit of the output module is obtained, so that the controller can be turned off. The self-correcting tuning fork sensing module of claim 4, wherein the feedback module has a phase difference of 90 degrees from the input end of the differential amplifier of the sensing module. The self-correcting tuning fork sensing module of claim 4, wherein the feedback module has a phase difference of 180 degrees from the input end of the differential amplifier of the sensing module. A method for self-correcting a tuning fork type sensing device, which is mainly executed by a controller according to any one of claims 1 to 6, which comprises: a. starting; b. initial procedure, reading built-in materials The voltage reference value; c. obtain the voltage value of a material signal; d. compare the voltage value, compare the voltage value of the c step with the voltage reference value, if not, perform the e step, if yes, execute h step; e. outputting a correction signal to increase or decrease an output voltage; f. obtaining a corrected voltage value; g. comparing the magnitude of the voltage value, comparing the corrected voltage value of the f step with a voltage reference value, if not , then perform the e step; h. output the material signal after the operation.